Rural tourism in professional and scientific literature is becoming increasingly important subject in the twenty first century. However, its terminological definition as well as all the related phenomena and terms are still insufficiently explored. The subject of this doctoral dissertation, as its main goal, tries to research and explain the terminological problem, and the role and significance of entrepreneurship in rural tourism. From a theoretical point of view, it was necessary to investigate and systematize the existing scientific knowledge in the field of rural tourism, sustainable development and entrepreneurship in tourism, and its significance and impact on the sustainable economic development of the rural area. The subject of this dissertation is related to the knowledge and research about the development of rural tourism and its sustainability through the implementation of entrepreneurial projects in the continental part of Croatia from the standpoint of experts and scientists in tourism and investors in entrepreneurial projects. Accordingly, the dissertation uses primary and secondary research to explain and point out the possibilities of tourism and economic assessment of entrepreneurship projects in rural tourism in the function of sustainable development of tourism in Croatia and selected European Union countries. Starting from the specifics of tourism as an entrepreneurial activity, the dissertation explores the role of entrepreneurship in the development of rural tourism in the area of continental Croatia. The continental rural area of Croatia stretches across thirteen counties, with the exception of the city of Zagreb as an extremely urban unit. Although tourism in Croatia has a high level of development, especially in the coastal region, the continental part of the rural area is severely lagging behind in the tourist and economic development, which is the result of the national tourism policy. Rural tourism is one of the least developed types of tourism in the Republic of Croatia, although over 90% of the country consists of rural areas. Agriculture, forestry and tourism have a special role in the economic development of continental Croatia as complementary activities and important drivers of rural development. Research has shown that entrepreneurial activities in these industries can lead to the economic growth of this area the fastest. Entrepreneurship in tourism in continental Croatia is developed in different capacities: tourist family farms, hotels, apartments, taverns, restaurants, winches etc. Considering the size and purchasing power of tourist demand, the fundamental problem for the development of entrepreneurship in Continental Croatia arises from low profitability or the inability to realize a profitable entrepreneurship in rural tourism. This questions the economic viability of businesses in tourism. Therefore, the purpose of this doctoral dissertation is to explore the conditions and emphasize the possibilities of profitable business operations of rural entrepreneurs using the concept of sustainable development. In order to apply the principles of sustainable development, existing and new entrepreneurial projects in rural tourism should apply to the ecological principles of sustainable development, socio-cultural principles, and in particular the economic principles of sustainable development of the destination. The results of the empirical analysis of the development of rural tourism in Continental Croatia on a sample of 35 respondents (tourism experts) show that rural tourism is developing without a plan, it is lagging behind the surrounding competing countries, and it is insufficiently utilizing its resource potential. This research and the secondary data confirm hypothesis H–1: Rural tourism is the least developed type of tourism in the Republic of Croatia. The obtained results show that rural tourism in Croatia is at the very outset in its share in the total tourist turnover as well as in relation to other types of tourism which are significant for Croatia’s tourist development. The main reason for this is the small share of tourist traffic in Continental Croatia and insufficient development of tourist offer. It has been established that continental Croatia has huge untapped potentials for rural tourism development which should be developed together with the development of other specific forms of tourism. This has resulted in the confirmation of hypothesis H-3: Rural tourism in the Republic of Croatia can only be developed as an integrated tourist product along with complementary development of specific forms of tourism. The analysis of secondary data on rural tourism development through comparative analysis in five EU countries has established that the level of its development is stronger and more intensive than in Croatia. Examples of good practice are studied in Austria, Italy, Slovenia, Spain and France. In this context, the hypothesis H-2 was accepted: The development of the existing tourism offer in rural tourism in Croatia, by content and quality, is significantly lagging behind the competing countries in the surrounding area. The second part of the primary research was conducted using a structured survey questionnaire on a sample of 30 entrepreneurs in rural tourism in Continental Croatia, except for the city of Zagreb, as an extremely urban area. The results of the research have shown that a high percentage of respondents believe that for long-term sustainable entrepreneurship in rural tourism, it is necessary to attain the profitability of entrepreneurial projects. This confirms hypothesis H-4: Long - term economic sustainability of rural tourism depends significantly on the profitability of entrepreneurial projects in selected tourist destinations. Theoretical and empirical research and presented results represent a significant contribution to the further sustainable development of rural tourism through the assessment of entrepreneurial projects, thus achieving a higher level of significance of the rural area for the national economy and a higher standard of living for the local population. The scientific contribution of this doctoral dissertation stems from the findings that point to the necessity of defining entrepreneurial projects that will determine the direction and intensity of the future sustainable development of rural tourism through entrepreneurial projects in Croatia and thus strengthen the competitiveness at both the national and international level.